Commit Graph

750 Commits

Author SHA1 Message Date
Reid Kleckner 9803178a78 Avoid Attr.h includes, CodeGen edition
This saves around 20 includes of Attr.h. Not much.
2019-12-09 16:17:18 -08:00
Craig Topper 505aa2410d [Attr] Move ParsedTargetAttr out of the TargetAttr class
Need to forward declare it in ASTContext.h for D68627, so it can't be a nested struct.

Differential Revision: https://reviews.llvm.org/D71159
2019-12-09 12:40:41 -08:00
Reid Kleckner eff08f4097 Revert "[Sema][X86] Consider target attribute into the checks in validateOutputSize and validateInputSize."
This reverts commit e1578fd2b7.

It introduces a dependency on Attr.h which I am removing from
ASTContext.h.
2019-12-06 15:42:14 -08:00
Craig Topper e1578fd2b7 [Sema][X86] Consider target attribute into the checks in validateOutputSize and validateInputSize.
The validateOutputSize and validateInputSize need to check whether
AVX or AVX512 are enabled. But this can be affected by the
target attribute so we need to factor that in.

This patch copies some of the code from CodeGen to create an
appropriate feature map that we can pass to the function. Probably
need some refactoring here to share more code with Codegen. Is
there a good place to do that? Also need to support the cpu_specific
attribute as well.

Differential Revision: https://reviews.llvm.org/D68627
2019-12-06 15:30:59 -08:00
Adrian Prantl 338588d7cf Debug Info: Apply a default location for cleanups if none is available.
This unbreaks the debuginfo-tests testsuite by replacing the assertion
with a default location. There are cleanups in helper functions that
don't have a valid source location such as block copy helpers and it's
not worth tracking each of them down.

rdar://57630879
2019-12-05 13:30:23 -08:00
Adrian Prantl ce7d35988d Debug Info: Assert that location is available for cleanups
rdar://57630879

Differential Revision: https://reviews.llvm.org/D71042
2019-12-05 12:45:10 -08:00
Melanie Blower 7f9b513847 Reapply af57dbf12e "Add support for options -frounding-math, ftrapping-math, -ffp-model=, and -ffp-exception-behavior="
Patch was reverted because https://bugs.llvm.org/show_bug.cgi?id=44048
        The original patch is modified to set the strictfp IR attribute
        explicitly in CodeGen instead of as a side effect of IRBuilder.
        In the 2nd attempt to reapply there was a windows lit test fail, the
        tests were fixed to use wildcard matching.

        Differential Revision: https://reviews.llvm.org/D62731
2019-12-05 03:48:04 -08:00
Melanie Blower 5412913631 Revert " Reapply af57dbf12e "Add support for options -frounding-math, ftrapping-math, -ffp-model=, and -ffp-exception-behavior=""
This reverts commit cdbed2dd85.
Build break on Windows (lit fail)
2019-12-04 12:21:23 -08:00
Melanie Blower cdbed2dd85 Reapply af57dbf12e "Add support for options -frounding-math, ftrapping-math, -ffp-model=, and -ffp-exception-behavior="
Patch was reverted because https://bugs.llvm.org/show_bug.cgi?id=44048
        The original patch is modified to set the strictfp IR attribute
        explicitly in CodeGen instead of as a side effect of IRBuilder

        Differential Revision: https://reviews.llvm.org/D62731
2019-12-04 11:32:33 -08:00
Akira Hatanaka f139ae3d93 [NFC] Pass a reference to CodeGenFunction to methods of LValue and
AggValueSlot

This reapplies 8a5b7c3570 after a null
dereference bug in CGOpenMPRuntime::emitUserDefinedMapper.

Original commit message:

This is needed for the pointer authentication work we plan to do in the
near future.

a63a81bd99/clang/docs/PointerAuthentication.rst
2019-12-03 15:22:13 -08:00
Akira Hatanaka 9f37c0e703 Revert "[NFC] Pass a reference to CodeGenFunction to methods of LValue and"
This reverts commit 8a5b7c3570. This seems
to have broken UBSan because of a null dereference.
2019-12-03 13:08:01 -08:00
Akira Hatanaka 8a5b7c3570 [NFC] Pass a reference to CodeGenFunction to methods of LValue and
AggValueSlot

This is needed for the pointer authentication work we plan to do in the
near future.

a63a81bd99/clang/docs/PointerAuthentication.rst
2019-12-03 11:30:09 -08:00
Erich Keane 0213adde21 [NFC] Fix 'target' condition in checkTargetFeatures
checkTargetFeatures was incorrectly checking for cpu_specific instead of
just 'target'. While this function was never called in that situation,
it seemed correct to fix the condition.  Additionally, multiversion
functions can never be always_inline, but if any function accidentially
ended up here we shouldn't diagnose.

Note that the adding of target-features to the list is unnecessary since
the getFunctionFeatureMap actually considers attribute target,
however adding it results in significantly better error messages by
putting the 'target' features first (and thus first to fail).
Otherwise, the error message would be the first feature 'implied' by the
target attribute, and not necessarily the feature listed in the
attribute itself.
2019-11-18 13:43:52 -08:00
Eric Christopher 30e7ee3c4b Temporarily Revert "Add support for options -frounding-math, ftrapping-math, -ffp-model=, and -ffp-exception-behavior="
and a follow-up NFC rearrangement as it's causing a crash on valid. Testcase is on the original review thread.

This reverts commits af57dbf12e and e6584b2b7b
2019-11-18 10:46:48 -08:00
Serge Pavlov e6584b2b7b Move floating point related entities to namespace level
Enumerations that describe rounding mode and exception behavior were
defined inside ConstrainedFPIntrinsic. It makes sense to use the same
definitions to represent the same properties in other cases, not only
in constrained intrinsics. It was however inconvenient as required to
include constrained intrinsics definitions even if they were not needed.
Also using long scope prefix reduced readability.

This change moves these definitioins to the namespace llvm::fp.
No functional changes.

Differential Revision: https://reviews.llvm.org/D69552
2019-11-15 19:56:33 +07:00
Adrian Prantl 2073dd2da7 Redeclare Objective-C property accessors inside the ObjCImplDecl in which they are synthesized.
This patch is motivated by (and factored out from)
https://reviews.llvm.org/D66121 which is a debug info bugfix. Starting
with DWARF 5 all Objective-C methods are nested inside their
containing type, and that patch implements this for synthesized
Objective-C properties.

1. SemaObjCProperty populates a list of synthesized accessors that may
   need to inserted into an ObjCImplDecl.

2. SemaDeclObjC::ActOnEnd inserts forward-declarations for all
   accessors for which no override was provided into their
   ObjCImplDecl. This patch does *not* synthesize AST function
   *bodies*. Moving that code from the static analyzer into Sema may
   be a good idea though.

3. Places that expect all methods to have bodies have been updated.

I did not update the static analyzer's inliner for synthesized
properties to point back to the property declaration (see
test/Analysis/Inputs/expected-plists/nullability-notes.m.plist), which
I believed to be more bug than a feature.

Differential Revision: https://reviews.llvm.org/D68108

rdar://problem/53782400
2019-11-08 08:23:22 -08:00
Melanie Blower af57dbf12e Add support for options -frounding-math, ftrapping-math, -ffp-model=, and -ffp-exception-behavior=
Add options to control floating point behavior: trapping and
    exception behavior, rounding, and control of optimizations that affect
    floating point calculations. More details in UsersManual.rst.

    Reviewers: rjmccall

    Differential Revision: https://reviews.llvm.org/D62731
2019-11-07 07:22:45 -08:00
Jonas Paulsson 9376714314 [Clang FE] Recognize -mnop-mcount CL option (SystemZ only).
Recognize -mnop-mcount from the command line and add a function attribute
"mnop-mcount"="true" when passed.

When this option is used, a nop is added instead of a call to fentry. This
is used when building the Linux Kernel.

If this option is passed for any other target than SystemZ, an error is
generated.

Review: Ulrich Weigand
https://reviews.llvm.org/D67763
2019-11-05 12:12:36 +01:00
Amy Huang ab76cfdd20 Recommit "[CodeView] Add option to disable inline line tables."
This reverts commit 004ed2b0d1.
Original commit hash 6d03890384

Summary:
This adds a clang option to disable inline line tables. When it is used,
the inliner uses the call site as the location of the inlined function instead of
marking it as an inline location with the function location.

https://reviews.llvm.org/D67723
2019-11-04 09:15:26 -08:00
Amy Huang 004ed2b0d1 Revert "[CodeView] Add option to disable inline line tables."
because it breaks compiler-rt tests.

This reverts commit 6d03890384.
2019-10-30 17:31:12 -07:00
Amy Huang 6d03890384 [CodeView] Add option to disable inline line tables.
Summary:
This adds a clang option to disable inline line tables. When it is used,
the inliner uses the call site as the location of the inlined function instead of
marking it as an inline location with the function location.

See https://bugs.llvm.org/show_bug.cgi?id=42344

Reviewers: rnk

Subscribers: hiraditya, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D67723
2019-10-30 16:52:39 -07:00
Erich Keane f759395994 Reland r374450 with Richard Smith's comments and test fixed.
The behavior from the original patch has changed, since we're no longer
allowing LLVM to just ignore the alignment.  Instead, we're just
assuming the maximum possible alignment.

Differential Revision: https://reviews.llvm.org/D68824

llvm-svn: 374562
2019-10-11 14:59:44 +00:00
Nico Weber b556085d81 Revert 374450 "Fix __builtin_assume_aligned with too large values."
The test fails on Windows, with

  error: 'warning' diagnostics expected but not seen:
    File builtin-assume-aligned.c Line 62: requested alignment
        must be 268435456 bytes or smaller; assumption ignored
  error: 'warning' diagnostics seen but not expected:
    File builtin-assume-aligned.c Line 62: requested alignment
        must be 8192 bytes or smaller; assumption ignored

llvm-svn: 374456
2019-10-10 21:34:32 +00:00
Erich Keane 31e454c1ec Fix __builtin_assume_aligned with too large values.
Code to handle __builtin_assume_aligned was allowing larger values, but
would convert this to unsigned along the way. This patch removes the
EmitAssumeAligned overloads that take unsigned to do away with this
problem.

Additionally, it adds a warning that values greater than 1 <<29 are
ignored by LLVM.

Differential Revision: https://reviews.llvm.org/D68824

llvm-svn: 374450
2019-10-10 21:08:28 +00:00
Graham Hunter b302561b76 [SVE][IR] Scalable Vector size queries and IR instruction support
* Adds a TypeSize struct to represent the known minimum size of a type
  along with a flag to indicate that the runtime size is a integer multiple
  of that size
* Converts existing size query functions from Type.h and DataLayout.h to
  return a TypeSize result
* Adds convenience methods (including a transparent conversion operator
  to uint64_t) so that most existing code 'just works' as if the return
  values were still scalars.
* Uses the new size queries along with ElementCount to ensure that all
  supported instructions used with scalable vectors can be constructed
  in IR.

Reviewers: hfinkel, lattner, rkruppe, greened, rovka, rengolin, sdesmalen

Reviewed By: rovka, sdesmalen

Differential Revision: https://reviews.llvm.org/D53137

llvm-svn: 374042
2019-10-08 12:53:54 +00:00
Guillaume Chatelet c79099e0f4 [Alignment][Clang][NFC] Add CharUnits::getAsAlign
Summary:
This is a prerequisite to removing `llvm::GlobalObject::setAlignment(unsigned)`.
This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

Reviewers: courbet

Subscribers: jholewinski, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D68274

llvm-svn: 373592
2019-10-03 13:00:29 +00:00
John McCall 36b12a861c Rename TypeNodes.def to TypeNodes.inc for consistency across all
our autogenerated files.  NFC.

As requested by Nico Weber.

llvm-svn: 373425
2019-10-02 06:35:23 +00:00
Erich Keane 856f3fe5bb Fix always_inline 'target' compatibility check code for Lambdas
The previous version of this used CurFuncDecl in CodeGenFunction,
however this doesn't include lambdas.  However, CurCodeDecl DOES. Switch
the check to use CurCodeDecl so that the actual function being emitted
gets checked, preventing an error in ISEL.

llvm-svn: 370261
2019-08-28 20:59:25 +00:00
Vitaly Buka 669d111c52 hwasan, codegen: Keep more lifetime markers used for hwasan
Reviewers: eugenis

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D66697

llvm-svn: 369980
2019-08-26 22:16:05 +00:00
Vitaly Buka aeca56964f msan, codegen, instcombine: Keep more lifetime markers used for msan
Reviewers: eugenis

Subscribers: hiraditya, cfe-commits, #sanitizers, llvm-commits

Tags: #clang, #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D66695

llvm-svn: 369979
2019-08-26 22:15:50 +00:00
Brian Gesiak f8d6836f7a [CodeGen] Disable UBSan for coroutine functions
Summary:
As explained in http://lists.llvm.org/pipermail/llvm-dev/2018-March/121924.html,
the LLVM coroutines transforms are not yet able to move the
instructions for UBSan null checking past coroutine suspend boundaries.
For now, disable all UBSan checks when generating code for coroutines
functions.

I also considered an approach where only '-fsanitize=null' would be disabled,
However in practice this led to other LLVM errors when writing object files:
"Cannot represent a difference across sections". For now, disable all
UBSan checks until coroutine transforms are updated to handle them.

Test Plan:
1. check-clang
2. Compile the program in https://gist.github.com/modocache/54a036c3bf9c06882fe85122e105d153
   using the '-fsanitize=null' option and confirm it does not crash
   during LLVM IR generation.

Reviewers: GorNishanov, vsk, eric_niebler, lewissbaker

Reviewed By: vsk

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D44672

llvm-svn: 368675
2019-08-13 12:02:25 +00:00
Peter Collingbourne 0e497d1554 cfi-icall: Allow the jump table to be optionally made non-canonical.
The default behavior of Clang's indirect function call checker will replace
the address of each CFI-checked function in the output file's symbol table
with the address of a jump table entry which will pass CFI checks. We refer
to this as making the jump table `canonical`. This property allows code that
was not compiled with ``-fsanitize=cfi-icall`` to take a CFI-valid address
of a function, but it comes with a couple of caveats that are especially
relevant for users of cross-DSO CFI:

- There is a performance and code size overhead associated with each
  exported function, because each such function must have an associated
  jump table entry, which must be emitted even in the common case where the
  function is never address-taken anywhere in the program, and must be used
  even for direct calls between DSOs, in addition to the PLT overhead.

- There is no good way to take a CFI-valid address of a function written in
  assembly or a language not supported by Clang. The reason is that the code
  generator would need to insert a jump table in order to form a CFI-valid
  address for assembly functions, but there is no way in general for the
  code generator to determine the language of the function. This may be
  possible with LTO in the intra-DSO case, but in the cross-DSO case the only
  information available is the function declaration. One possible solution
  is to add a C wrapper for each assembly function, but these wrappers can
  present a significant maintenance burden for heavy users of assembly in
  addition to adding runtime overhead.

For these reasons, we provide the option of making the jump table non-canonical
with the flag ``-fno-sanitize-cfi-canonical-jump-tables``. When the jump
table is made non-canonical, symbol table entries point directly to the
function body. Any instances of a function's address being taken in C will
be replaced with a jump table address.

This scheme does have its own caveats, however. It does end up breaking
function address equality more aggressively than the default behavior,
especially in cross-DSO mode which normally preserves function address
equality entirely.

Furthermore, it is occasionally necessary for code not compiled with
``-fsanitize=cfi-icall`` to take a function address that is valid
for CFI. For example, this is necessary when a function's address
is taken by assembly code and then called by CFI-checking C code. The
``__attribute__((cfi_jump_table_canonical))`` attribute may be used to make
the jump table entry of a specific function canonical so that the external
code will end up taking a address for the function that will pass CFI checks.

Fixes PR41972.

Differential Revision: https://reviews.llvm.org/D65629

llvm-svn: 368495
2019-08-09 22:31:59 +00:00
Evgeniy Stepanov c5e7f56249 ARM MTE stack sanitizer.
Add "memtag" sanitizer that detects and mitigates stack memory issues
using armv8.5 Memory Tagging Extension.

It is similar in principle to HWASan, which is a software implementation
of the same idea, but there are enough differencies to warrant a new
sanitizer type IMHO. It is also expected to have very different
performance properties.

The new sanitizer does not have a runtime library (it may grow one
later, along with a "debugging" mode). Similar to SafeStack and
StackProtector, the instrumentation pass (in a follow up change) will be
inserted in all cases, but will only affect functions marked with the
new sanitize_memtag attribute.

Reviewers: pcc, hctim, vitalybuka, ostannard

Subscribers: srhines, mehdi_amini, javed.absar, kristof.beyls, hiraditya, cryptoad, steven_wu, dexonsmith, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D64169

llvm-svn: 366123
2019-07-15 20:02:23 +00:00
Erich Keane 36176249d1 Ensure Target Features always_inline error happens in C++ cases.
A handful of C++ cases as reported in PR42352 didn't actually give an
error when always_inlining with a different target feature list. This
resulted in broken IR.

llvm-svn: 364109
2019-06-21 22:29:32 +00:00
Amy Huang 7fac5c8d94 Store a pointer to the return value in a static alloca and let the debugger use that
as the variable address for NRVO variables.

Subscribers: hiraditya, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D63361

llvm-svn: 363952
2019-06-20 17:15:21 +00:00
Richard Smith e637cbe4e4 Refactor: split Uninitialized state on APValue into an "Absent" state
representing no such object, and an "Indeterminate" state representing
an uninitialized object. The latter is not yet used, but soon will be.

llvm-svn: 361328
2019-05-21 23:15:18 +00:00
Anastasia Stulova e6cf6c78f8 [OpenCL] Make global ctor init function a kernel
We need to be able to enqueue internal function that initializes
global constructors on the host side. Therefore it has to be
converted to a kernel.

This change factors out common logic for adding kernel metadata
and moves it from CodeGenFunction to CodeGenModule in order to
make it accessible for the extra use case.

Differential revision: https://reviews.llvm.org/D61488

llvm-svn: 360342
2019-05-09 13:55:44 +00:00
Leonard Chan c72aaf62d3 Recommit r359859 "[Attribute/Diagnostics] Print macro if definition is an attribute declaration"
Updated with fix for read of uninitialized memory.

llvm-svn: 360109
2019-05-07 03:20:17 +00:00
Leonard Chan ef2dc25a96 Revert "[Attribute/Diagnostics] Print macro if definition is an attribute declaration"
This reverts commit fc40cbd9d8.

llvm-svn: 359859
2019-05-03 03:28:06 +00:00
Leonard Chan fc40cbd9d8 [Attribute/Diagnostics] Print macro if definition is an attribute declaration
If an address_space attribute is defined in a macro, print the macro instead
when diagnosing a warning or error for incompatible pointers with different
address_spaces.

We allow this for all attributes (not just address_space), and for multiple
attributes declared in the same macro.

Differential Revision: https://reviews.llvm.org/D51329

llvm-svn: 359826
2019-05-02 20:38:14 +00:00
John McCall 8b36ac818c Don't emit an unreachable return block.
Patch by Brad Moody.

llvm-svn: 358104
2019-04-10 17:03:09 +00:00
James Y Knight 8799caee8d [opaque pointer types] Trivial changes towards CallInst requiring
explicit function types.

llvm-svn: 353009
2019-02-03 21:53:49 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Roman Lebedev bd1c087019 [clang][UBSan] Sanitization for alignment assumptions.
Summary:
UB isn't nice. It's cool and powerful, but not nice.
Having a way to detect it is nice though.
[[ https://wg21.link/p1007r3 | P1007R3: std::assume_aligned ]] / http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p1007r2.pdf says:
```
We propose to add this functionality via a library function instead of a core language attribute.
...
If the pointer passed in is not aligned to at least N bytes, calling assume_aligned results in undefined behaviour.
```

This differential teaches clang to sanitize all the various variants of this assume-aligned attribute.

Requires D54588 for LLVM IRBuilder changes.
The compiler-rt part is D54590.

This is a second commit, the original one was r351105,
which was mass-reverted in r351159 because 2 compiler-rt tests were failing.

Reviewers: ABataev, craig.topper, vsk, rsmith, rnk, #sanitizers, erichkeane, filcab, rjmccall

Reviewed By: rjmccall

Subscribers: chandlerc, ldionne, EricWF, mclow.lists, cfe-commits, bkramer

Tags: #sanitizers

Differential Revision: https://reviews.llvm.org/D54589

llvm-svn: 351177
2019-01-15 09:44:25 +00:00
Vlad Tsyrklevich 86e68fda3b Revert alignment assumptions changes
Revert r351104-6, r351109, r351110, r351119, r351134, and r351153. These
changes fail on the sanitizer bots.

llvm-svn: 351159
2019-01-15 03:38:02 +00:00
Roman Lebedev 7892c37455 [clang][UBSan] Sanitization for alignment assumptions.
Summary:
UB isn't nice. It's cool and powerful, but not nice.
Having a way to detect it is nice though.
[[ https://wg21.link/p1007r3 | P1007R3: std::assume_aligned ]] / http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p1007r2.pdf says:
```
We propose to add this functionality via a library function instead of a core language attribute.
...
If the pointer passed in is not aligned to at least N bytes, calling assume_aligned results in undefined behaviour.
```

This differential teaches clang to sanitize all the various variants of this assume-aligned attribute.

Requires D54588 for LLVM IRBuilder changes.
The compiler-rt part is D54590.

Reviewers: ABataev, craig.topper, vsk, rsmith, rnk, #sanitizers, erichkeane, filcab, rjmccall

Reviewed By: rjmccall

Subscribers: chandlerc, ldionne, EricWF, mclow.lists, cfe-commits, bkramer

Tags: #sanitizers

Differential Revision: https://reviews.llvm.org/D54589

llvm-svn: 351105
2019-01-14 19:09:27 +00:00
Brian Gesiak 5488ab4ddd [AST] Remove ASTContext from getThisType (NFC)
Summary:
https://reviews.llvm.org/D54862 removed the usages of `ASTContext&` from
within the `CXXMethodDecl::getThisType` method. Remove the parameter
altogether, as well as all usages of it. This does not result in any
functional change because the parameter was unused since
https://reviews.llvm.org/D54862.

Test Plan: check-clang

Reviewers: akyrtzi, mikael

Reviewed By: mikael

Subscribers: mehdi_amini, dexonsmith, cfe-commits

Differential Revision: https://reviews.llvm.org/D56509

llvm-svn: 350914
2019-01-11 01:54:53 +00:00
Erich Keane 2a4eea3061 [NFC] Fix usage of Builder.insert(new Bitcast...)in CodeGenFunction
This is exactly a "CreateBitCast", so refactor this to get rid of a
'new'.

Note that this slightly changes the test, as the Builder is now
seemingly smart enough to fold one of the bitcasts into the annotation
call.

Change-Id: I1733fb1fdf91f5c9d88651067130b9a4e7b5ab67
llvm-svn: 349506
2018-12-18 16:22:21 +00:00
Reid Kleckner 43071080cd Remove unused Args parameter from EmitFunctionBody, NFC
llvm-svn: 349001
2018-12-13 01:33:20 +00:00
Erich Keane 8c94f07f54 Teach __builtin_unpredictable to work through implicit casts.
The __builtin_unpredictable implementation is confused by any implicit
casts, which happen in C++.  This patch strips those off so that
if/switch statements now work with it in C++.

Change-Id: I73c3bf4f1775cd906703880944f4fcdc29fffb0a
llvm-svn: 348969
2018-12-12 20:30:53 +00:00